I am going to purchase a refregerator and freezer, I want the one largest in size, having the least noise and making cool with the least waste of energy among all the brands. In fact I want the best in quality and the largest refregerator and freezer.
Which brand should I buy?

The problem with asking individuals for advice is that they often relate to their own experience, and not to what is available in the market place.
Fortunately there are many comparable product reviews available on the Internet.

You do not state why you need "the largest" fridge-freezer. For home or business?
Another thought : don't you need cool water and an ice block dispenser?
What is your budget? The largest fridge-freezers are intended for professional use, and sell in the order of $ 4000,00 and more.
You first have to list everything you want your fridge-freezer to have and do.
With that list I suggest you "google" your answer by entering the following search words :

comparison fridge-freezers

Use Google, and not other search engines. At least if you want the best results...

Success !

:)